Part of the Apple/FBI court case involves how software updates are protected with digital signatures. The key ensures that the update comes from Apple and therefore has a level of trust associated with the history of the company. The government is not asking Apple to turn over the signing key and Apple is not likely to do that. But if Apple agrees to use the key whenever the government insists, the trust level about what is in their software updates is decreased.

On the other hand, the trust level could both be increased and at least somewhat divorced from government intervention by distributing additional signing keys to some highly trusted public groups that are willing to examine the software update and confirm some level of integrity. These “witness” signatures from trusted external sources would accumulate more trust that backdoors are not being installed or some other secret agenda is not being followed.

It might also be worthwhile investigating how the blockchain technology being used in cybercurrency could be incorporated into this idea. And this scheme of witnessing signatures could add trust to a variety of other applications.

Today companies might have one signing key, or several keys in the hands of a few trusted employees who must come together to sign a new update. Ford has developed a system that can create hundreds or thousands of signing keys intended to be distributed more widely, even to people at other companies or public-interest organizations such as the Electronic Frontier Foundation.

Under that model, when Apple created and signed a new update it would pause before distributing it to ask for additional “witness” signatures from other people it had granted keys to. Whether or not diverse witnesses provided their signatures would signal to the security community whether this was a routine update or something unusual, says Ford.